LONDON, Nov 4 (Reuters) - British new car registrations fell to their lowest October level since 1991 after a 25% year-on-year drop as a lack of semi-conductor chips continued to hit the sector, according to industry figures released on Thursday. Full-year sales are expected to stand at 1.66 million vehicles, only 1.9% higher than 2020, when COVID-19 lockdowns and restrictions were in place, the Society of Motor Manufacturers and Traders (SMMT) said. A total of 106,265 vehicles were registered last month. The worldwide chip shortage has forced many brands to cut production and increased the waiting times for some buyers as carmakers grapple with the fallout from the pandemic. "The current performance reflects the challenging supply constraints, with the industry battling against semiconductor shortages and increasingly strong economic headwinds as inflation rises, taxes increase and consumer confidence has weakened," said SMMT Chief Executive Mike Hawes. Reporting by Costas Pitas; Editing by Kate Holton